Field
Aspects of the present disclosure relate generally to local oscillator clock generation, and more particularly, to 25% duty cycle local oscillator clock generation circuits and methods.
Background
Mixers are used in a variety of RF/microwave applications, including military radar, cellular base stations, cellular mobile stations, and more. An RF mixer is a three-port passive or active device that can modulate or demodulate a signal. The purpose is to change the frequency of an electromagnetic signal while (hopefully) preserving every other characteristic (such as phase and amplitude) of the initial signal. The three ports are referred to as the RF input port, local oscillator clock input port, and the IF (intermediate frequency) output port. A mixer is also known as a downconverter if the mixer is part of a receiver or as an upconverter if it is part of a transmitter.
The local oscillator clocks are used by one or more mixers to change the frequency of an RF signal. The local oscillator clock generation circuit must produce a stable frequency with low harmonics. Stability must take into account temperature, voltage, and mechanical drift as factors. The local oscillator clock generation circuit must produce enough output power to effectively drive subsequent stages of circuitry, such as mixers or frequency multipliers.
Accordingly, it would be beneficial to provide an improved circuits and methods of local oscillator clock generation that reduce power consumption and improve noise performance.